IMPLEMENTATION OF NEW PARAMETRIZATIONS FOR ORGANIC AEROSOL MODELLING BY CAMX: CASE STUDY FOR THE SUMMER PERIOD IN THE PO VALLEY

Abstract

This work presents the results of simulations conducted with the CAMx model for the reconstruction of organic aerosol in the Po Valley using the chemical schemes SOAP and VBS. With this latter scheme, simulations have also been developed introducing new parameterizations for the calculation of emissions of organic compounds with intermediate volatility, and revising of the emissions of primary organic aerosol and the related volatility distributions. The simulations concerned the period from May to July 2013. Composition data of the organic aerosol obtained from the PMF analysis of data from measurement campaigns carried out in San Pietro Capofiume (BO) and Ispra (VA) were used to validate the results. With reference to the overall organic aerosol, the comparison with the experimental data showed that the transition to the VBS scheme and the introduction of revisions and new emission parameters did not produce evident effects on the results of the summer simulations, unlike the winter case, discussed in previous studies. This essentially because the changes introduced concern anthropogenic emissions, in particular those from biomass combustion, which in summer are much less important than in winter while, on the contrary, emissions of biogenic origin increase. Furthermore, an influence of the greater partitioning of the organic aerosol towards the gaseous phase in the summer period cannot be excluded.